The invention relates to a jet regulator having a jet regulator housing, in the housing interior of which a flow straightener is provided, said flow straightener having at least one insert part that is insertable into the housing interior, said insert part having a grid structure which is formed from a set of radially oriented webs which intersect or are in contact with a set of concentrically encircling webs at intersection points or contact points, and having at least one aeration opening which passes through a housing circumferential wall of the jet regulator.
Various jet regulators have already been created, which can be mounted at the water outlet of a sanitary outlet fitting in order to form the water emerging there from the outlet fitting into a homogeneous, non-splashing water jet. A distinction is drawn here between non-aerated and aerated jet regulator embodiments. In aerated jet regulators, the water flowing therethrough is intermixed with ambient air in the regulator housing of the jet regulator, in order to allow the water to emerge as a gentle bubbling water jet.
To this end, such aerated jet regulators have a jet splitter in their jet regulator housing, said jet splitter dividing the water flowing in into a multiplicity of individual jets. These individual jets have their speed increased in the jet splitter, such that a negative pressure arises on the outflow side of the jet splitter in accordance with the Bernoulli equation. Aeration openings are provided in the circumferential wall of the jet regulator housing on the outflow side of the jet splitter, said aeration openings passing through the circumferential wall. The negative pressure that arises on the outflow side of the jet splitter draws in the ambient air, which passes through the aeration openings and into the housing interior of the jet regulator housing and is intermixed with the individual jets there, before the individual jets intermixed with air in this way are formed into an aerated overall jet in a flow straightener.
This flow straightener usually is formed of at least two insert parts which are insertable in the housing interior of the jet regulator housing. These insert parts each have a lattice or grid structure which initially divides the aerated individual jets flowing therethrough even further. However, the lattice- or grid-like insert parts that form the flow straightener also represent an obstacle to flow, upstream of which the water flowing through can back up. Undesired noises occur occasionally in the process. These disruptive noises, which are perceptible as gurgling or groaning noise, are caused by the build-up at intervals of a film of water in the aeration openings, which are briefly closed by this film of water. Due to the negative pressure on the outflow side of the jet splitter in the region of the aeration openings, this film of water breaks down again immediately after it has formed and is drawn into the throughflow region of the jet regulator. The constant high-frequency build-up and breakdown of the film of water results in these flow noises or disruptive noises. The insert parts of the flow straightener, which at the same time form an obstacle to flow, result in a flow backup at the outer attachment of the lattice or grid structure in the region of the external retaining ring. A kind of “ramp” forms there, which causes the water to back up upstream of the aeration openings. During the build-up and breakdown of the film of water in the housing interior upstream of the aeration openings, small quantities of water also regularly emerge from the aeration openings in the form of aerosol water or splashing water. This emerging water can result in increased limescale formation and in external soiling of the jet regulator or of the outlet nozzle that accommodates the jet regulator.